Radiation with a wavelength of 308 nm shines on a metal surface and ejects electrons that have a maximum speed of 3.08e15 m/s. What type of metal is being hit by the 308 nm radiation? The values in parentheses are the candidate metal work functions: potassium (2.24 eV), calcium (2.71 eV), uranium (3.63 eV), aluminum (4.08 eV), or gold (4.82 eV). Use the photoelectric equation hf= KEmax + W0.